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DTSTART:16011104T020000
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BEGIN:VEVENT
ATTENDEE;CN="ARB (310) RESEARCH DIVISION";RSVP=TRUE:mailto:310@arb.ca.gov
ATTENDEE;CN="ARB (352) Economic Studies";RSVP=TRUE:mailto:352@arb.ca.gov
ATTENDEE;CN="ARB (360) RESEARCH PLANNING AND CLIMATE CHANGE MITIGATION BRAN
CH";RSVP=TRUE:mailto:360@arb.ca.gov
ATTENDEE;CN="ARB (362) Climate Change Mitigation and Emissions Research";RS
VP=TRUE:mailto:362@arb.ca.gov
ATTENDEE;CN="ARB (363) Climate Action And Research Planning";RSVP=TRUE:mail
to:363@arb.ca.gov
ATTENDEE;CN="ARB (364) Greenhouse Gas Reduction Strategy";RSVP=TRUE:mailto:
364@arb.ca.gov
ATTENDEE;CN="ARB (370) HEALTH AND EXPOSURE ASSESSMENT BRANCH";RSVP=TRUE:mai
lto:370@arb.ca.gov
ATTENDEE;CN="ARB (371) Populations Studies";RSVP=TRUE:mailto:371@arb.ca.gov
ATTENDEE;CN="ARB (372) Indoor Exposure Assessment";RSVP=TRUE:mailto:372@arb
.ca.gov
ATTENDEE;CN="ARB (373) Health and Ecosystems Assessment";RSVP=TRUE:mailto:3
73@arb.ca.gov
ATTENDEE;CN="ARB (374) Library";RSVP=TRUE:mailto:374@arb.ca.gov
ATTENDEE;CN="ARB (380) AIR QUALITY FIELD STUDIES AND ADMINISTRATION BRANCH"
;RSVP=TRUE:mailto:380@arb.ca.gov
ATTENDEE;CN="ARB (381) Greenhouse Gas Technology and Field Testing";RSVP=TR
UE:mailto:381@arb.ca.gov
ATTENDEE;CN="ARB (382) Atmospheric Processes Research";RSVP=TRUE:mailto:382
@arb.ca.gov
ATTENDEE;CN="ARB (383) Administrative";RSVP=TRUE:mailto:383@arb.ca.gov
ATTENDEE;CN="ARB (384) Air Quality and Climate Science";RSVP=TRUE:mailto:38
4@arb.ca.gov
CLASS:PUBLIC
CREATED:20130619T175853Z
DESCRIPTION:Veerabhadran Ramanathan\, Ph.D.\, and Lynn M. Russell\, Ph.D.\,
Scripps Institution of Oceanography\, University of California\, San Dieg
o\n\nhttp://www.arb.ca.gov/research/seminars/ramanathan/ramanathan.htm\n\n
Nehzat Motallebi\, contact\nPeter Mathews\, Series contact\n\nABSTRACT: Bl
ack carbon (BC) is the most strongly light-absorbing component of particul
ate matter (PM)\, and is formed by the incomplete combustion of fossil fue
ls\, biofuels\, and biomass. Black carbon contributes to the adverse impa
cts on human health\, ecosystems\, and visibility associated with PM2.5. T
oday’s seminar summarizes the results of two research projects on assess
ment of the impact of BC on the regional radiative forcing and climate tre
nds of California. Dr. Ramanathan will present the principal findings and
implications resulting from a three year multi-institutional regional inte
grated assessment of the climate and air pollution effects of black carbon
. It is the first such attempt to estimate the radiative forcing of BC for
California\, both from a bottom-up approach (starting with emission inven
tory as input to aerosol-transport models) and a top-down approach (adopti
ng satellite data in conjunction with ground based column averaged aerosol
optical properties). This approach reveals three unanticipated major find
ings:\n\n i) the first finding concerns the large decadal trends in BC co
ncentrations largely in response to policies enacted to decrease PM emissi
ons from diesel combustion\;\n \n ii) the second is the finding that the
climate cooling effects of reductions in black carbon were not offset by
reductions in organic and sulfate particles\; and\n \n iii) the discover
y of the large effects of brown carbon (a form of organic carbon aerosols)
on radiative forcing.\n\nThe major implication of this study is that redu
ctions in emissions of BC mostly from diesel engines\, since the 1980s hav
e contributed to a measurable mitigation of anthropogenic global warming\,
equivalent to the mitigation of 21 million metric tons of CO2 emissions a
nnually and could be as high as 50 million tons annually. Because of the l
ong lifetime of CO2 (one century or longer) compared with the much shorter
lifetime of BC (about one week)\, mitigation of CO2 is critical for limit
ing long term global warming\, while mitigation of BC is critical for limi
ting near-term warming. Dr. Russell will discuss the relative importance
of the first indirect aerosol effect of BC forcing for California’s clim
ate. BC particles could also indirectly cause changes in the absorption or
reflection of solar radiation through changes in the properties and behav
ior of clouds. The results of the study show that reducing BC particle co
ncentration by 50% decreased the cloud droplet concentration by between 6%
and 9% resulting in the formation of fewer\, larger cloud droplets that c
orrespond to a lower cloud albedo. The implications of this comparison are
that in addition to total number concentration\, the size and composition
of BC-containing particles is also a significant factor in determining th
e net impact on clouds. For regions like California\, where BC mitigation
targets primarily fossil fuel sources\, the cloud albedo effect of BC part
icles may partially offset the climate benefits of direct forcing reductio
n. But the cloud-burning effects of BC can enhance the climate benefits of
direct forcing reduction\, having the opposite effect.\n
DTEND;TZID="Pacific Standard Time":20130723T153000
DTSTAMP:20130619T161357Z
DTSTART;TZID="Pacific Standard Time":20130723T133000
LAST-MODIFIED:20130619T175853Z
LOCATION:Sierra Hearing Room
ORGANIZER;CN="Mathews, Peter@ARB":mailto:pmathews@arb.ca.gov
PRIORITY:5
SEQUENCE:0
SUMMARY;LANGUAGE=en-us:Seminar - "Black Carbon Reductions in California and
its Implications for Regional and Global Climate Change Mitigation" (Abs
tract below)
TRANSP:OPAQUE
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0100000001944B3E2A1F00244999B45532877B93D
X-ALT-DESC;FMTTYPE=text/html:">\n\n

ABSTRACT:&nbsp\;&nbsp\;&nbsp\;&nbsp\;&nbsp\;&nbsp\;<
SPAN LANG="en-us"> Black carbon (BC) is the most stro
ngly light-absorbing component of particulate matter (PM)\, and is formed
by the incomplete combustion of fossil fuels\, biofuels\, and biomass.&nbs
p\; Black carbon contributes to the adverse impacts on human health\, ecos
ystems\, and visibility associated with PM2.5. Today’s seminar summarize
s the results of two research projects on assessment of the impact of BC o
n the regional radiative forcing and climate trends of California. Dr. Ram
anathan will present the principal findings and implications resulting fro
m a three year multi-institutional regional integrated assessment of the c
limate and air pollution effects of black carbon. It is the first such att
empt to estimate the radiative forcing of BC for California\, both from a
bottom-up approach (starting with emission inventory as input to aerosol-t
ransport models) and a top-down approach (adopting satellite data in conju
nction with ground based column averaged aerosol optical properties). This
approach reveals three unanticipated major findings:

\n<
UL DIR=LTR>

\n

i) the first finding concerns the large decadal trends in BC concentrati
ons largely in response to policies enacted to decrease PM emissions from
diesel combustion\;

\n\n

\n\n

ii) the sec
ond is the finding that the climate cooling effects of reductions in black
carbon were not offset by reductions in organic and sulfate particles\; a
nd

\n\n

\n\n

iii) the discovery of the la
rge effects of brown carbon (a form of organic carbon aerosols) on radiati
ve forcing.

\n

\n

<
/SPAN>

\n\n

The major
implication of this study is that reductions in emissions of BC mostly fr
om diesel engines\, since the 1980s have contributed to a measurable mitig
ation of anthropogenic global warming\, equivalent to the mitigation of 21
million metric tons of CO2 emissions annually and could be as high as 50
million tons annually. Because of the long lifetime of CO2 (one century or
longer) compared with the much shorter lifetime of BC (about one week)\,
mitigation of CO2 is critical for limiting long term global warming\, whil
e mitigation of BC is critical for limiting near-term warming.&nbsp\; Dr.
Russell will discuss the relative importance of the first indirect aerosol
effect of BC forcing for California’s climate. BC particles could also
indirectly cause changes in the absorption or reflection of solar radiatio
n through changes in the properties and behavior of clouds.&nbsp\; The res
ults of the study show that reducing BC particle concentration by 50% decr
eased the cloud droplet concentration by between 6% and 9% resulting in th
e formation of fewer\, larger cloud droplets that correspond to a lower cl
oud albedo. The implications of this comparison are that in addition to to
tal number concentration\, the size and composition of BC-containing parti
cles is also a significant factor in determining the net impact on clouds.
For regions like California\, where BC mitigation targets primarily fossi
l fuel sources\, the cloud albedo effect of BC particles may partially off
set the climate benefits of direct forcing reduction. But the cloud-burnin
g effects of BC can enhance the climate benefits of direct forcing reducti
on\, having the opposite effect.